The reconstruction of bone substance losses, mainly resulting from trauma and, more rarely, tumor, is one of the major difficulties encountered by orthopedic surgeons. Small defects, from “tight” pseudarthrosis (faulty consolidation of a fracture where the loss of substance is virtual) up to bone losses of 5-6 cm, are most commonly the subject of an autologous graft of spongy or cortical-spongy bone tissues taken from the iliac crest (gold standard). Large defects (≧6 cm) require much more cumbersome procedures, vascularized bone transfers or a Masquelet procedure. Even so, the amount of autologous bone that is available is limited, the bone consolidation remains random and these various techniques are very much purveyors of post-operative complications at the site where the graft is taken.
Various biomaterials available in clinical practice make it possible to avoid, in theory, the drawbacks of autologous grafting. Unfortunately, none of them equals the results of bone grafting and they never enable the reconstruction of large losses of substances.
The majority of the materials currently studied combine, with the biomaterials, mesenchymal stem cells obtained from bone marrow after several weeks of selection and cell culture in vitro. This approach is laborious and expensive, which limits the clinical uses.
It is known that coagulated blood promotes bone reconstruction. L. Okazaki et al., Clin. Oral Impl. Res., 16, 2005, 236-243 describes implants based on coagulated blood or demineralized bone powder. Document WO 02/068010 describes a bone marrow-based composite material, this material comprising a porous, biocompatible implantable matrix and a coagulated material, such as a bone marrow, blood or plasma coagulate.
Such materials, resulting from the combination of a support and of coagulated or noncoagulated blood, have up until now been used in maxillofacial surgery where the problems of bone consolidation are not so important, but have been used little or not at all in the repair of diaphyseal bones.
The methods for producing these implants require blood to be taken from a donor, most commonly the individual for whom the implant is intended, and then require steps in which the support (demineralized bone or synthetic polymer, ceramic) is handled, in particular steps of mixing with the blood, which are sources of contamination of the biomaterial. In addition, it is difficult to obtain a homogeneous biomaterial by means of these methods.
There thus remains the need for a method for preparing an implantable biomaterial from a support which is synthetic, and therefore easy to produce, with constant and homogeneous properties, this method making it possible to obtain properties that are superior in terms of biocompatibility and enabling the rapid reconstruction of a bone tissue of quality, without it being necessary to use culturing or sampling steps.